I. Field of the Invention
This invention relates to a process for the polymerization of vinyl chloride in aqueous dispersion, and to the products resulting therefrom.
II. Description of the Prior Art
The polymerization of vinyl chloride in bulk and in aqueous dispersion is a well known operation. Suspension polymerization involves the dispersion of the monomer in the form of large droplets in water with a protective agent or colloid, such as methyl cellulose and a polymerization oil soluble initiator such as benzoyl peroxide and effecting the dispersion of these droplets in water by mechanical agitation. The polymeric material which is formed during the polymerization reaction is in the form of large particles coated with the protective agent. The dispersion of the droplets and particles formed during the polymerization reaction is not very stable when the agitation is stopped. The polymeric particles which are obtained by suspension polymerization generally have a mean diameter between about 10.mu. and 500.mu. and preferrably between about 50.mu. and 300.mu.. Emulsion polymerization involves the dispersion of the monomer and of the polymer in the form of fine droplets or particles by means of emulsifying agents, such as sodium laurate. The emulsifying agents are generally used in an amount so that the aqueous dispersion remains stable for a certain period of time after the agitation is stopped. The polymerization reaction is generally initiated by a water soluble polymerization initiator such as ammonium persulfate. The polymeric particles formed are fine and generally have a diameter between about 0.02.mu. and 2.mu..